He packs his things and leaves then shows up 3 weeks later?

I don't know him or any other extenuating cirstances of your relationship but from this brief description he sounds like a jerk. Oh I accidentally took the Shampoo? Give me a break! How many other things did he accidentally take so that in another week when he's hungry or horny he can come over again to "return" them. UGH! Cut him loose. It will hurt, you will cry, you will think you will never love again and want to crawl in a hole an die but those feelings will p and in a year from now you're gonna say "What the HELL was I thinking"!!!